[PATCH 03/10] net: emac: use DMA-specific and SMP memory barriers
From: Rosen Penev <hidden>
Date: 2026-06-30 04:16:41
Also in:
lkml
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Replace generic wmb()/mb() barriers with more specific variants: - dma_wmb() for ordering descriptor field writes before hardware ownership bit (ctrl) hand-off in TX/RX paths - dma_rmb() for ordering descriptor ctrl read after ownership observation in the RX poll path - smp_wmb() for CPU-to-CPU ordering (link_polling flag, platform_set_drvdata visibility) - dma_rmb() for the RX descriptor ownership transfer read Assisted-by: opencode:big-pickle Signed-off-by: Rosen Penev <redacted> --- drivers/net/ethernet/ibm/emac/core.c | 16 ++++++++-------- drivers/net/ethernet/ibm/emac/mal.c | 2 +- drivers/net/ethernet/ibm/emac/rgmii.c | 2 +- drivers/net/ethernet/ibm/emac/tah.c | 2 +- drivers/net/ethernet/ibm/emac/zmii.c | 4 ++-- 5 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/ibm/emac/core.c b/drivers/net/ethernet/ibm/emac/core.c
index 1d46cf6c2c12..5e7b85d28bde 100644
--- a/drivers/net/ethernet/ibm/emac/core.c
+++ b/drivers/net/ethernet/ibm/emac/core.c@@ -1185,7 +1185,7 @@ __emac_prepare_rx_skb(struct sk_buff *skb, struct emac_instance *dev, int slot) dev->rx_desc[slot].data_ptr = dma_map_single(&dev->ofdev->dev, skb->data - NET_IP_ALIGN, dev->rx_sync_size, DMA_FROM_DEVICE) + NET_IP_ALIGN; - wmb(); + dma_wmb(); dev->rx_desc[slot].ctrl = MAL_RX_CTRL_EMPTY | (slot == (NUM_RX_BUFF - 1) ? MAL_RX_CTRL_WRAP : 0);
@@ -1263,7 +1263,7 @@ static int emac_open(struct net_device *ndev) link_poll_interval = PHY_POLL_LINK_OFF; } dev->link_polling = 1; - wmb(); + smp_wmb(); schedule_delayed_work(&dev->link_work, link_poll_interval); emac_print_link_status(dev); } else
@@ -1464,7 +1464,7 @@ static netdev_tx_t emac_start_xmit(struct sk_buff *skb, struct net_device *ndev) skb->data, len, DMA_TO_DEVICE); dev->tx_desc[slot].data_len = (u16) len; - wmb(); + dma_wmb(); dev->tx_desc[slot].ctrl = ctrl; return emac_xmit_finish(dev, len);
@@ -1560,7 +1560,7 @@ emac_start_xmit_sg(struct sk_buff *skb, struct net_device *ndev) /* Send the packet out */ if (dev->tx_slot == NUM_TX_BUFF - 1) ctrl |= MAL_TX_CTRL_WRAP; - wmb(); + dma_wmb(); dev->tx_desc[dev->tx_slot].ctrl = ctrl; dev->tx_slot = (slot + 1) % NUM_TX_BUFF;
@@ -1671,7 +1671,7 @@ static inline void emac_recycle_rx_skb(struct emac_instance *dev, int slot, DMA_FROM_DEVICE); dev->rx_desc[slot].data_len = 0; - wmb(); + dma_wmb(); dev->rx_desc[slot].ctrl = MAL_RX_CTRL_EMPTY | (slot == (NUM_RX_BUFF - 1) ? MAL_RX_CTRL_WRAP : 0); }
@@ -1754,7 +1754,7 @@ static int emac_poll_rx(void *param, int budget) break; skb = dev->rx_skb[slot]; - mb(); + dma_rmb(); len = dev->rx_desc[slot].data_len; if (unlikely(!MAL_IS_SINGLE_RX(ctrl)))
@@ -1845,7 +1845,7 @@ static int emac_poll_rx(void *param, int budget) } if (unlikely(budget && test_bit(MAL_COMMAC_RX_STOPPED, &dev->commac.flags))) { - mb(); + dma_rmb(); if (!(dev->rx_desc[slot].ctrl & MAL_RX_CTRL_EMPTY)) { DBG2(dev, "rx restart" NL); received = 0;
@@ -3167,7 +3167,7 @@ static int emac_probe(struct platform_device *ofdev) /* Set our drvdata last as we don't want them visible until we are * fully initialized */ - wmb(); + smp_wmb(); platform_set_drvdata(ofdev, dev); printk(KERN_INFO "%s: EMAC-%d %pOF, MAC %pM\n",
diff --git a/drivers/net/ethernet/ibm/emac/mal.c b/drivers/net/ethernet/ibm/emac/mal.c
index 4025bc36ae16..99615c8a6c3e 100644
--- a/drivers/net/ethernet/ibm/emac/mal.c
+++ b/drivers/net/ethernet/ibm/emac/mal.c@@ -691,7 +691,7 @@ static int mal_probe(struct platform_device *ofdev) mal->num_tx_chans, mal->num_rx_chans); /* Advertise this instance to the rest of the world */ - wmb(); + smp_wmb(); platform_set_drvdata(ofdev, mal); return 0;
diff --git a/drivers/net/ethernet/ibm/emac/rgmii.c b/drivers/net/ethernet/ibm/emac/rgmii.c
index b544dd8633b7..093aa4f129e3 100644
--- a/drivers/net/ethernet/ibm/emac/rgmii.c
+++ b/drivers/net/ethernet/ibm/emac/rgmii.c@@ -255,7 +255,7 @@ static int rgmii_probe(struct platform_device *ofdev) ofdev->dev.of_node, (dev->flags & EMAC_RGMII_FLAG_HAS_MDIO) ? "" : "out"); - wmb(); + smp_wmb(); platform_set_drvdata(ofdev, dev); return 0;
diff --git a/drivers/net/ethernet/ibm/emac/tah.c b/drivers/net/ethernet/ibm/emac/tah.c
index ed07532aaf85..077da56fa449 100644
--- a/drivers/net/ethernet/ibm/emac/tah.c
+++ b/drivers/net/ethernet/ibm/emac/tah.c@@ -112,7 +112,7 @@ static int tah_probe(struct platform_device *ofdev) tah_reset(ofdev); printk(KERN_INFO "TAH %pOF initialized\n", ofdev->dev.of_node); - wmb(); + smp_wmb(); return 0; }
diff --git a/drivers/net/ethernet/ibm/emac/zmii.c b/drivers/net/ethernet/ibm/emac/zmii.c
index a3839cf02ec4..5144ee94a7d2 100644
--- a/drivers/net/ethernet/ibm/emac/zmii.c
+++ b/drivers/net/ethernet/ibm/emac/zmii.c@@ -258,8 +258,8 @@ static int zmii_probe(struct platform_device *ofdev) /* Disable all inputs by default */ out_be32(&dev->base->fer, 0); - printk(KERN_INFO "ZMII %pOF initialized\n", ofdev->dev.of_node); - wmb(); + dev_info(&ofdev->dev, "ZMII initialized\n"); + smp_wmb(); platform_set_drvdata(ofdev, dev); return 0;
--
2.54.0